1. Field of the Disclosure
The present disclosure relates to semiconductor integrated circuits for use in devices where it is desirable to prevent unauthorized manufacture of copies of those devices.
2. Description of the Related Art
Semiconductor integrated circuits, conveniently referred to below simply as ‘circuits’, are ubiquitous in modern electronic devices including mobile telephones, pay-television systems, and many other widely used devices. One problem faced by manufacturers of these kinds of devices is that unscrupulous traders attempt to manufacturer and sell illegitimate copies of such devices, drawing valuable custom away from the legitimate device manufacturer. Legitimate device manufacturers typically purchase circuits from another party and assemble them according to their own design. Copying of electronic devices by illegitimate parties, known as cloning, is achieved by obtaining the necessary components and assembling them into an exact copy of the physical circuit board of the device manufacturer, thereby creating an unauthorized copy of the whole device. The software from the original device, executed by a circuit in the device allowing the device to function, is then copied to the cloned device.
A solution to this problem is for the device manufacture to use software that is unique to themselves and for the manufacturer of the circuits to provide circuits that will properly execute only the software of that particular device manufacturer. Such an arrangement may be described as providing a circuit that is personalized to a circuit to a device manufacturer's unique software. In this scheme, different device manufacturers use different software and so require circuits that are personalized to that different software. In this way, so long as the circuit manufacturer supplies circuits personalized to a particular device manufacturer's software only to that device manufacturer, cloning of devices is prevented. This is because when an illegitimate party constructs a copy of a legitimate device and copies the software from that device, the circuit comprised in the copied device would not be correctly personalized to the copied software since correctly personalized circuits would only be supplied to the legitimate device manufacturer and the illegitimate party would therefore not be able to obtain them.
One problem with this approach is that the manufacture of a different circuit design type is required for each end device manufacturer. This involves the time consuming process of testing each separate circuit type at the manufacturing stage and the logistical difficulty in distributing the appropriate circuit to each device manufacturer.
We have appreciated the need to prevent circuits sold for use in a device from operating in a copy of that device. We have also appreciated the need for a method for distributing circuits that are personalized whilst avoiding the problems mentioned above.